WQ #16

Which of the following particles has the lowestmass? a. a neutrino b. a proton c. a neutron d. an electron e. the nucleus of a hydrogen atom

a. a neutrino

If the "fuel" for nuclear fusion is nuclei of hydrogen, and the Earth's oceans are filled with hydrogen atoms in water all being jostled together, why isn't there a lot of fusion happening in our oceans? a. the hydrogen in our oceans is the wrong type of hydrogen for fusion b. for hydrogen nuclei to fuse, they must get veryclose to each other, which the nuclei in the oceans cannot do c. for hydrogen to fuse, the nuclei must first join together in long chains of atoms d. on Earth, only hydrogen that is in deep mines under the Earth is far enough underground for fusion e. you can't fool me, hydrogen in the Earth's oceans does undergo fusion; that's what keeps our oceans warm

b. for hydrogen nuclei to fuse, they must get veryclose to each other, which the nuclei in the oceans cannot do

What happens to the positron created during the p-p chain of nuclear reactions inside the Sun? a. it merges with a proton to become a deuterium (heavy hydrogen) nucleus b. it quickly collides with an electron and turns into gamma-ray energy c. it ultimately forms an anti-helium nucleus d. it turns quickly into a neutrino, which can escape from the Sun e. it just sits there at the core of the Sun for billions of years, unable to interact

b. it quickly collides with an electron and turns into gamma-ray energy

When energy is first produced by fusion deep in the core of the star, that energy moves outward mostly by what process? a. convection b. radiation c. conduction d. theoretical modeling e. none of the above

b. radiation

Which of the following is a way for astronomers to learn more about the interior of the Sun? a. study the corona during eclipses of the Sun b. study the oscillations (pulsations) of the Sun's surface c. follow the orbit of Mercury, the closest planet to the Sun d. take photographs of the Sun in the light absorbed by hydrogen atoms e. study the accounts in ancient legends of the realm where the devil is supposed to live

b. study the oscillations (pulsations) of the Sun's surface

Which part of the Sun has the greatest density? a. the photosphere b. the core c. the convection region d. the corona e. you can't fool me; all the Sun's parts have the same density

b. the core

If it takes an average of 14 billion years before any proton inside the Sun will undergo fusion, and the Sun is only about 5 billion years old, why do astronomers believe that fusion is going on there now? a. fusion begins with particles even lighter than protons, which fuse more easily b. there are an enormous number of protons inside the Sun, and some of them will fuse much sooner than the average c. much more fusion takes place in the hot atmosphere of the Sun (where it can happen faster), not deep inside (where fusion is slow) d. most of the fusion inside the Sun involves carbon, not protons; carbon fuses much more quickly e. there is no fusion going on inside the Sun, and the fact given in the question is one of the reasons why

b. there are an enormous number of protons inside the Sun, and some of them will fuse much sooner than the average

Astronomers and physicists now believe they know what is happening to the missing neutrinos from the Sun (the neutrinos that our theories say should be emerging from the Sun, but our experiments in that underground mine could not find). These neutrinos are: a. not being produced by the Sun because our star's nuclear fusion period has ended b. turning into a different type of neutrino in a neutrino oscillation c. being converted to antimatter in the core of the Sun and being destroyed as they hit matter d. changing course before they reach the Earth as they hit other neutrinos in space e. all aimed at Bayonne, New Jersey, and our neutrino experiments are located elsewhere

b. turning into a different type of neutrino in a neutrino oscillation

Who pays the bill for the energy generated by nuclear fusion in the Sun? In other words, where does the energy pouring out of the Sun come from ultimately? a. the Sun is spinning more slowly as time goes on; rotation energy is lost b. heavy nuclei are breaking apart into lighter nuclei c. a little bit of mass is lost in each fusion reaction and is turned into energy (the Sun is losing mass) d. material (like meteorites) is falling into the Sun and being vaporized to produce energy e. American taxpayers pay this bill, as they do so many others!

c. a little bit of mass is lost in each fusion reaction and is turned into energy (the Sun is losing mass)

Which of the following statements about helioseismology experiments is FALSE: a. the pulsations these experiments measure take about an hour to emerge from the Sun's interior b. small changes in the velocity of the waves of pulsation coming from inside the Sun help astronomers figure out the structure of the Sun's interior c. helioseismology measures waves that are set up by the motion of neutrinos from the core of the Sun d. a typical pulsation takes about 5 minutes to complete a full cycle from maximum to minimum speed and back again e. Helioseismology allows astronomers to look under a sunspot and see how it works

c. helioseismology measures waves that are set up by the motion of neutrinos from the core of the Sun

The Sun is an enormous ball of gas. Left to itself, a ball of so many atoms should collapse under its own tremendous gravity. Why is our Sun not collapsing? a. the gravity of the planets around the Sun pulls its material outward, preventing collapse b. the pressure of the corona keeps the Sun's main body of gases confined to a small volume c. nuclear fusion in the core keeps the temperature and the pressure inside the Sun at a high enough level so that gravity is balanced d. neutrinos from the core exert an enormous pressure on the layers of the Sun as they travel outward; this pressure is more than enough to keep our star from collapsing e. you can't fool me, the Sun is shrinking all the time, it just happens very slowly

c. nuclear fusion in the core keeps the temperature and the pressure inside the Sun at a high enough level so that gravity is balanced

The material inside the Sun is in the form of a a. solid b. liquid c. plasma d. ball of iron atoms e. none of the above

c. plasma

Which of the following is NOT one of the fundamental particles that we find inside atoms? a. protons b. neutrons c. positrons d. electrons e. all four of the above are found in most atoms

c. positrons

The strongest force we know is a. gravity, which holds the Earth and the Sun together b. electricity, which pulls unlike charges together c. the nuclear force which holds nuclei together d. the attraction of Bayonne, New Jersey, for tourists e. none of the above

c. the nuclear force which holds nuclei together

A college friend of yours who has been postponing taking any science courses hears you talking about the generation of nuclear energy in the Sun and makes the following observation: "The whole idea of the atomic nucleus is pretty ridiculous. If an oxygen nucleus consists of eight protons and eight neutrons, the charge on that nucleus is positive. Since even I learned in high school that like charges repel, such a nucleus would find all its positive protons repelling and quickly fall apart." How would you answer his argument? a. gravity is much stronger than electric repulsion and holds every nucleus together b. the neutrons in the nucleus are negative, so they cancel the positive charge on the protons c. the nuclear force, which is attractive over short distances like the nucleus, and stronger than electricity, holds the nucleus together d. the electrons outside the nucleus repel the protons and keep them inside the nucleus e. there is no answer; scientists do not have a clue about how the nucleus manages to keep itself together

c. the nuclear force, which is attractive over short distances like the nucleus, and stronger than electricity, holds the nucleus together

At the end of the p-p chain of nuclear fusion in the Sun, hydrogen nuclei have been converted into: a. carbon nuclei b. heavy hydrogen nuclei c. antimatter and nothing else d. a helium nucleus e. a lithium nucleus

d. a helium nucleus

The Global Oscillations Network Group (GONG) Project is engaged in: a. measuring where earthquakes happen around the Earth by the waves they generate b. measuring the number of sunspots on the surface of the Sun at any given hour c. measuring the quality of the "seeing" (the "jiggling" of the Earth's atmosphere) at all the major observatories around the world d. measuring the pulsations of the Sun from stations around the world e. measuring how problems on the World Wide Web are affecting the communication among astronomers

d. measuring the pulsations of the Sun from stations around the world

Which of the following statements about antimatter is true? a. antimatter is only a theory, we have no evidence that it exists b. antimatter only exists in Earth laboratories; it cannot be made in stars c. antimatter cannot be made in laboratories; we have tried but it just can't be done d. when a particle of matter and the corresponding particle of antimatter meet, they become pure energy e. our telescopes clearly see many nearby antimatter stars in the Milky Way galaxy

d. when a particle of matter and the corresponding particle of antimatter meet, they become pure energy

Which of the following is NOT a product of the first step in the p-p chain of nuclear fusion? a. a form of hydrogen b. a positron c. neutrino d. a deuteron e. a form of helium

e. a form of helium

In the Sun, when a positron and an electron collide, they will produce: a. a deuteron b. a neutron c. hydrogen d. a neutron e. energy in the form of a gamma ray

e. energy in the form of a gamma ray

In the formula E=mc2, the letter c stands for a. the speed of sound b. the speed of an electron around the nucleus c. the amount of energy contained in one hydrogen nucleus d. the energy of a neutrino emerging from the Sun e. the speed of light

e. the speed of light